§1031 Like-Kind Exchange Calculator (2026)

Model deferred gain, boot recognition, and basis carryover for real property exchanges under IRC §1031. Tracks the 45-day identification and 180-day replacement deadlines and enforces the post-TCJA real-property-only restriction.

Guidance, not advice. This calculator runs the rules as published, it doesn't assess your circumstances. Your actual tax may be affected by factors it doesn't cover (deductions, credits, filing status nuances, state-specific adjustments). Always seek financial or tax advice from a qualified CPA, Enrolled Agent, or tax attorney, or contact the IRS. Read our editorial scope →

Post-TCJA real-property-only restriction

Since January 1, 2018, §1031 exchanges apply only to real property. Personal property — equipment, vehicles, artwork, aircraft, franchise rights — no longer qualifies. If you are exchanging personal property, this calculator will not apply §1031 treatment.

Relinquished property (old)

The property you are selling or exchanging away.

Adjusted basis

Purchase price + capital improvements − depreciation taken.

Fair market value at sale

Contract sale price or appraised value.

Mortgage balance relieved

Outstanding mortgage the buyer pays off or assumes.

Replacement property (new)

The like-kind property you are acquiring.

Fair market value

Contract purchase price or appraised value.

New mortgage assumed

Mortgage you take on the replacement property.

Cash received (cash boot)

Any cash or non-like-kind property you receive back.

Property type

Real property (land, buildings, improvements) — qualifies under §1031

Personal property (equipment, vehicles, art, intangibles) — disallowed post-TCJA

Exchange summary

Amount realized$1,200,000

Less: Adjusted basis−$400,000

Realized gain$800,000

Cash boot$0

Net mortgage relief$0

Total boot received$0

Recognized gain

Taxed now

Deferred gain

$800,000

Rolled into replacement

Adjusted basis — replacement property

$800,000

= FMV − deferred gain = adj. basis − recognized + boot + new mortgage

Full deferral

No boot received. The entire $800,000 realized gain is deferred into the replacement property. You will pay tax only when you eventually sell the replacement property without another §1031 exchange.

Qualified Intermediary (QI) is mandatory

You cannot touch the sale proceeds. Under §1031(a)(3), the QI must hold the funds between closing of the relinquished property and closing of the replacement property. Taking constructive receipt — even briefly — disqualifies the exchange.

§1031 Timeline tracker

45-day identification and 180-day replacement deadlines are calendar-day counts — including weekends and holidays. No extensions except for federally declared disasters.

Days elapsed since relinquished property closed

Day 0

Relinquished property closes

Start

Identification deadline

Hard deadline

45d away

180

Replacement must close

Hard deadline

180d away

Tax year 2026 · USD · OBBBA permanent law

Formula: Recognized gain = min(Realized gain, Cash boot + Net mortgage relief). Deferred gain = Realized gain − Recognized gain. Replacement basis = Adj. basis − Recognized + Boot + New mortgage.

Assumptions

Applies only to real property exchanges under §1031(a)(1) post-TCJA (2018+). Personal property does not qualify.
Assumes a simultaneous or deferred (forward) exchange. Reverse exchanges (replacement acquired first) have different mechanics and tighter deadlines.
Mortgage relief boot computed as max(0, old mortgage − new mortgage). Does not model wrap-around mortgages or seller financing intricacies.
Does not account for state-level clawback rules (e.g., California does not recognize §1031 deferral for state tax).
Related-party exchange restrictions (§1031(f)) and holding-period safe harbours (2 years) are not modeled.

Estimates only — not tax advice. Brackets, deductions and thresholds reflect the locked 2026 federal configuration. State amounts use each state's posted 2026 top-line rules and may differ from a full state-form computation. Always confirm complex situations with a qualified CPA, EA, or tax attorney.